The present disclosure relates generally to determining similar user identifiers.
Information about online users is often unavailable to interested parties, such as website owners and online advertisers. From an advertiser's perspective, placing an advertisement on a web page may or may not be of interest or useful for the end users viewing the web page. In some systems, the content of a web page may be used to help advertisers select advertisements to be provided with the web page. For example, an advertiser selling golf clubs may advertise on a website devoted to golf, since visitors to the website may share a common interest in golf. Such systems may use keywords located in the text of the website to identify topics discussed on the website.